John Hopkins

And then, when the surface is tantalizingly close, there is another problem.

He's struck by a new, terrifying pain.

A sharp stab in his left knee, a classic sign of the bends.

There's no more time.

After some negotiation with the medics, Don agrees to cut his decompression in the water short and take his chances on dry land.

And so, 12 and a half hours after beginning his dive, he finally lets the team pull him from the water and into the warm evening air.

Utterly depleted and unable to walk, Don is placed on a gurney, then hoisted up the slopes with a rope and pulley system and taken to the mobile recompression chamber above.

He is mated out of Bushman's Hole, but that doesn't mean his battle is over.

He remains in the claustrophobic, oxygen-rich chamber until the early hours of the morning.

When he is eventually able to emerge, it becomes clear quite how serious his condition is.

Before he collapses in his bed, Don is briefly able to phone his wife, Andre, who has been kept informed of his situation throughout the day.

In the midst of the grief around Dave's death, there is one central question.

What went wrong?

As it turns out, it isn't long before an answer is revealed.

In the days following the accident, some of the team begin retrieving the lines and gas cylinders that remain in the chamber.

As they pull the shot line up, the movement dislodges Dave's body from the bottom of the cave and he floats up towards the surface.

And, suspended below him by a thin cave line tangled around Dave's scuba gear, is D'Andrea.

After the bodies are retrieved, attention turns to the camera Dave was wearing.

The footage shows his dive went entirely to plan until he tried to place Dion into the body bag, at which point both he and the body became unexpectedly ensnared in the cave line.

During the struggle to free himself from the tangle, Dave's breathing grew heavier, increasing the amount of CO2 he was emitting into his rebreather.